Cesc Fabregas and Diego Costa were making their debuts for the Blues, with the latter pulling his team level after the break to cancel out Nik Kapun's first-half goal.

And it was another new boy, this time defender Kurt Zouma, who grabbed Chelsea's second as they ran out winners.

The scoreline could have been more impressive, too, after Branislav Ivanovic saw his effort ruled out shortly after Zouma had struck.

Reacting quickest to a rebound in the box, Ivanovic had scrambled the ball over the line, although it was ruled out seemingly for a foul on the goalkeeper from John Terry, despite the ball having crossed the line before the infringement.

Fernando Torres should have made it 3-1 late on, missing from three yards when he chested Nathan Ake's powerful cross over the bar.

In fairness to Torres, the speed of the ball gave him very little time to adjust his body and guide his effort, but being so close to an open net, he will be disappointed not to have found himself on the scoresheet.

Next up for Chelsea is a trip to Holland, where they face Vitesse Arnhem on Wednesday, so as Jose Mourinho plans ahead, we reflect on what the Chelsea boss learned from his team's victory in Slovenia.

Cesc Fabregas Can Play in the Pivot

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Chelsea lined up against Olimpija Ljubljana in their familiar 4-2-3-1 formation on Sunday.

No surprises there, then, but what was of interest is the fact that Jose Mourinho started Cesc Fabregas alongside Nemanja Matic in the midfield pivot.

Since the Spaniard joined the Blues, there has been much debate about where he will be deployed: Will he feature behind the striker or further back to get attacks started?

The fact that Fabregas started deep when just Mohamed Salah is the only recognized first-team attacking midfielder available hints that Mourinho is opting for the latter.

It worked, too.

Chelsea didn't look at their sharpest during the first half, but Fabregas performed well enough in his new role to suggest he will be a success there for the Blues.

His vision was excellent, and he was always looking to get the ball forward quickly, picking out the likes of Ozzy Brown, Salah and Diego Costa.

4-3-3 Is a Good Option

As has been the case during pre-season, there were a number of substitutions, but also a system change, switching from 4-2-3-1 to 4-3-3.

That gave Diego Costa support from Fernando Torres and Mohamed Salah either side of him and meant the Blues looked a far bigger threat going forward.

They also seemed to have a better shape in midfield, lining up with Marco van Ginkel, Nemanja Matic and Cesc Fabregas.

Indeed, it was Fabregas who assisted Costa for his first Chelsea goal, too, finding himself further forward than he had been in the first half, putting his Spanish teammate clear.

Chelsea went on to win the game 2-1 and Mourinho would have been happy with the experiment, seeing how effective his team can be when playing more offensively.

Diego Costa Isn't Going to Be a Flop

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It's a bold statement to make, but after just one game, Diego Costa has the look of a man who's at ease playing for Chelsea.

He arrives with a considerable reputation and transfer fee, but he doesn't seem fazed.

His goal on 55 minutes is exactly what we have come to expect from the Spanish international, playing off the last man to break into space and fire home beyond the goalkeeper.

It was a bright start.

Given Chelsea's track record with strikers recently, Jose Mourinho will be encouraged to see his star man already among the goalscorers.

Mohamed Salah Needs to Shoot More

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With Andre Schurrle, Eden Hazard, Oscar and Willian all yet to return from World Cup duty, Mohamed Salah has been given the perfect opportunity to impress Jose Mourinho and earn a starting berth for the start of the season.

If his pre-season form continues, though, he will not have done himself any favors.

The Egyptian has been frustrating thus far, consistently getting into good positions yet failing to make it count.

In Chelsea's previous three matches, Salah had opportunities to score but didn't because of poor decision-making. Against Olimpija Ljubljana, we saw much of the same.

It sounds simple, but Salah needs to shoot more. He needs to act more on instinct rather than over-playing, something he has been guilty of recently.

If he improves in that area, his goal tally will increase considerably and Chelsea will be far better off for it.

Chelsea's Squad Is Complete

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Chelsea had the likes of Diego Costa, Cesc Fabregas and Gary Cahill in their starting line-up against Olimpija Ljubljana on Sunday.

And the subs bench was packed with the considerable talents of John Terry, Branislav Ivanovic, Petr Cech and Fernando Torres.

Add the remaining World Cup stars who are yet to return from international duty, and the strength of Chelsea's squad looks formidable.

Jose Mourinho doesn't need to add any new faces now. Chelsea are all set and ready for 2014/15 and, after another victory, look a pretty good prospect for claiming a fifth league crown.

The only work the Chelsea boss will have to do over the coming weeks is decide whom to sell, as the Blues are well stocked across the pitch.

Chelsea Seem to Enjoy Digging a Hole for Themselves

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In three straight pre-season matches, Chelsea have conceded the first goal.

Against AFC Wimbledon, they were behind after just 40 seconds, while midweek against RZ Pellets, they trailed at half-time.

It was the same against Olimpija Ljubljana, Nik Kapun putting the home team ahead.

After that goal is when we saw the best from Chelsea, coming out after the interval to totally dominate and win the game 2-1.

It's clearly not a tactic, but Jose Mourinho needs to address his team's need to fall behind before they turn on the style. In a bigger game, against better opposition, they won't always have enough to get themselves out of jail.

Youth Has a Role to Play Next Season

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Despite so many big names back at Chelsea after the World Cup, it was refreshing to see Jose Mourinho keep faith with many of his younger players against Olimpija Ljubljana.

Izzy Brown and Jeremie Boga, both 17 years old, started in attacking midfield, while Patrick Bamford and Dominic Solanke were second-half substitutes.

Jose Mourinho seems intent on giving these talented young players an opportunity and equally, they seem intent on not letting him down.

Brown impressed against Olimpija Ljubljana, as did Bamford and Solanke, who were a handful for the defence after their introductions.

Boga didn't impact the game as much as he would have liked, but after his equalizer against Pellets in midweek, he is another player who has the look of doing something for Chelsea.

Garry Hayes is Bleacher Report's lead Chelsea correspondent. Follow him on Twitter @garryhayes